This is the second submission of a VA HSR&D CDA proposal to provide five years of salary support to Guneet K. Jasuja, PhD toward her goal of becoming a VA independent investigator and expert on medication prescribing research. Dr. Jasuja is a research health scientist in the HSR&D Center for Healthcare Organization and Implementation Research (CHOIR). This proposal delineates the research and training objectives that will lead to Dr. Jasuja's maturation into an independent health services researcher while contributing to the quality of care for Veterans. The first aim is to elucidate quantitative patient-, provider-, and site-level predictor of potentially inappropriate testosterone prescribing that to date have not been explored. Analyses will be conducted using administrative data on all male Veteran patients without HIV, who had at least one outpatient visit and one prescription fill during FY08-FY14. We will apply Generalized Linear Mixed Models to examine our putative predictors at the patient- (e.g. depression), provider- (e.g. older age) and site-level (e.g. academic affiliation). The second aim is to examine patient, provider, and key opinion leader perceptions and system-level factors that relate to testosterone prescribing, using qualitative methods. For this study, we will conduct semi- structured interviews with patients, providers, and site-level thought leaders to gain additional insight into how their perceptions, as well as site factors, may influence testosterone prescribing. To effect meaningful change in prescribing, the results of the first two research aims will be combined with relevant findings in the literature to develop and pilot test a multi-faceted intervention to promote appropriate use of testosterone in the VA. The research proposed here will improve quality of care by limiting testosterone therapy to those patients most likely to benefit and least likely to be harmed. Investigating the context of testosterone prescribing and factors that contribute to suboptimal prescribing practices would be an important preparatory step before designing and implementing interventions to optimize testosterone therapy for those men in whom it is medically indicated. Findings from these studies will yield heretofore unknown information about several key aspects of potentially inappropriate testosterone prescribing, enabling future HSR&D research proposals to address similar medication prescribing issues. Lessons learnt from this study will also serve as an exemplar for other medications, which embody similar characteristics, including high cost and potential safety issues. In conjunction with the proposed research aims, the CDA will address key training objectives that will further develop Dr. Jasuja's research capabilities. These training objectives will provide formal and hands-on education in qualitative and implementation research methods. The carefully chosen mentorship team, selected for their knowledge and experience in the methodologies and content areas addressed in the proposal, is dedicated to fostering Dr. Jasuja's successful transition to an independent investigator. Drs. Rose and Bhasin have an established working relationship as current mentors on Dr. Jasuja's VISN 1 CDA, and Drs. Bokhour and Gifford have provided guidance and advice for several years. All are committed to the career development of Dr. Jasuja and the need for protected research time, as described in their attached letters. CHOIR has also committed resources to accomplish the objectives in the proposal. Dr. Jasuja's initial contribution will be to understand the factors that contribute to variation and overuse in testosterone across VA. In the long term, she will apply these skills more generally to the issue of reducing variation and overuse in other areas of care. The long-term outcome will be significant improvements in safe, effective, and high-quality medication prescribing to reduce adverse outcomes for Veterans.